Relay



Oct- 25, 1949 J. E. wlLLlNG ET AL 2,486,086

RELAY Filed Aug. 2l, 1945 l u l l Non-mag- L52`F 1 12 netc Non-magneticFIGA.

45 65IN V EN TORS.

JEWH lig and GJJohanek MMM Their ATTORNEY Patented Oct. 25, 1949 RELAYJoseph E. WillingA and George J. Johanek, Rochester, N. Y., assigner: toGeneral Railway Signal Company, Rochester, N. Y.

Application August 21, 1945, Serial No. 611,782

4 Claims. l

This invention relates to relays and more particularly to a relay of theneutral retained type.

By the term neutral retained when used in connection with relays ismeant a relay structure in which a neutral armature will not release inresponse to pole changing of the energizing circuitoi the relay. It isquite common, particularly in. railway signalling practice, to employ aneutral relay, that is, a relay which will be picked up irrespective ofthe direction of direct current now through its windings to manifest theilow of current in a circuit which circuit is also used for controllinga polar electro-responsive device, and where it is desired to have suchneutral relay remain picked up during pole changing of the current insuch circuit. In other words, the neutral relay is to manifest whetheror not current is mowing in the circuit irrespective of its direction;whereas, the polar device may be such as to operate only if the currentis of one polarity or may be a device which will operate in a particularmanner depending upon the polarity of the current now in the circuit.When a neutral relay is used 'in a circuit of this type, it is quiteoften necessary that Ithe relay not drop momentarily to its retractedposition due to a sudden change in the polarity of the current flowingin the circuit. It is, of course, understood that an ordinary neutrairelay of the tractive armature type will in most instances momentarilyassume its retracted position due to pole changing of its energizingcircuit and in railway signalling such momentary operation of a relay toits deenergized position may cau`se a signal to momentarily give thewrong indication. Also, since it is quite common practice for one signalto be controlled `by the next signal in advance such momentary droppingof a relay may cause a so-called tumble-down of signal indications tooccur. What is meant by tumble-down of signal indications is that amomentary change in a signal indication will cause the next signal inthe rear to produce a similar momentary change of signal indication andthis may be repeated ad iniinitum or at least to the end of a particularportion of the signal system. This is, of course, very undesirable andmust be avoided.

Sometimes the neutral armature in a neutralpolar relay is provided withmeans for causing it to be retained during pole changing of theenergizing current for the relay. A relay of this type is known as aretained neutral-polar relay. The

patent to Larson No. 1,852,210 dated April 5, 1932 armature of a neutralrelay not drop to its retracted position during pole changing of theenergizing circuit, but it is also highly desirable that such armatureshould remain in its attracted position in spite of momentary opening ofits energizing circuit. The relay disclosed in the Larson patent doesnot satisfy this latter requirement. This shortcoming in the Larsonpatent was overcome in the patent to Hitchcock, No. 2,056,147, datedSeptember 29, 1936 by providing a rectier in the energizing circuit ofthe small auxiliary magnet which acted to retain the main armature upboth during pole changing and momentary opening of the energizingcircuit of the relay. Rectiiiers are, however, not tolerated on somerailway signalling systems by reason of their susceptibility to damageby lightning disturbances, or the like.

In view of the foregoing and other important considerations, it isproposed to provide a relay the neutral armature of which will not bemomentarily dropped due to either pole changing of its energizingcircuit or momentary opening of its energizing circuit and which doesnot employ rectiiiers. @ne object of the present invention resides inthe provision of two polar relay structures each including a permanentmagnet and both acting on a single soft iron armature and so connectedin series or multiple that current of one polarity will render one ofthese structures eective and current of the other polarity will renderthe other structure eiective together with means for rendering each ofthese polar structures slow releasing.

Another object of the present invention resides in the provision of sucha permanent magnet between the poles of a soft iron yoke in a relaystructure such that the soft iron yoke normally serves as a shunt forthe ux emitted by such permanent magnet as a result of which theelectro-magnet responds only if current of one polarity is appliedthereto, and to employ two such electro-magnets to actuate a singlearmature regardless of the polarity of such current.

Another object of the present invention resides in the provision ofleakage strips adjacent the permanent magnet just mentioned so that thepermanent magnet is less apt to be demagnetized by excessive currentsuch as might occur due to a lightning disturbance or the like.

In accordance with one form of the present invention a three-pole softiron yoke. is provided between the middle and each outside pole oppositewhich are provided permanent magnets between the poles so that the backyoke of this `nate in enlarged pole pieces 20, 2| and 22.

relay structure serves as a magnetic shunt for both of the permanentmagnets employed.

Other objects, purposes and characteristic features of the presentinvention will in part be described hereinafter and will in part beobvious from the accompanying drawings, in which- Fig. i illustrates inelevation a relay embodying the present invention;

Fig. 2 shows a side view of the relay shown in Fig. 1;

Fig. 3 shows the relay illustrated in Fig. 1 with its energizing circuitenergized by current of one polarity and its armature in the attractedposition; and

Fig. 4 shows a modified form of the relay illustrated in Fig. 1.

The drawings have been devised to illustrate the invention more for thepurpose of showing the necessary structural characteristics of the relaythan showing the detailed design of a commercial device. For this reasonthe drawings have been made fragmentary in nature eliminating, i'orinstance, the housing for protecting the relay structure againstweather, the terminal blocks for supporting the fixed contacts andlead-in and lead-out wires of the relay and the coil structure; it beingbelieved that a disclosure and explanation of the essential structuralcharacteristics will be sufficient for an understanding of theprinciples of the invention so that they may be readily adapted to anyparticular relay designed for specific purposes, such as railwaysignalling, or the like.

Structure-Figs. 1, 2 and 3.-Referring to Figs. l, 2 and 3 of thedrawings the soft iron core structure Ill-I2 of the relay illustrated isof the threepole type the outer two legs I and I2 of which are providedwith coils I3 andwhereas the middle leg II is provided only withconducting washers or slugs I6 which function to render the relay slowdropping in the usual manner. The outside legs III and I2 are similarlyprovided with metallic washers or slugs I and I1 respectively. Directlyabove conducting washers I5 and I6 and between the legs I0 and II isprovided a permanent magnet PMI to bridge the airgap between these legsIII and II. A similar permaent magnet PM2 is arranged between the legsII` and I2 and directly over the slugs I6 and I'I. These permanentmagnets are preferably of the very high coercive force type and arepreferably constructed of the material known in the trade as Alnico butmay be of any other well-known type such as chrome steel or cobalt. IfAlnico is used the type known as Black Streak which has exceptionallyhigh coercive force may be used, if desired. These permanent magnets PMIand PM2 are preferably partially shunted by leakage strips LSI and LS2.This electro-magnet structure of the retained neutral relay of thepresent invention may be similar to that disclosed in the priorapplication of Duffy, Ser. No. 542,203, filed June 26, 1944, now PatentNo. 2,414,- 583, dated January 21, 1947, to which reference may be had.The three legs I0, II and I2 of the relay core structure preferablytermi- As more clearly shown in Fig. 2 of the drawings the armature A isprovided with a movable contact which may engage either a back fixedcontact 2l or a front fixed contact 26. The armature A is preferablypivoted, as shown, by the pin 28 extending into a fixed bracket 30 ofnon-magnetc material secured to the poles 20 and 22 as through themedium of screws 28.

-ly the same as heretofore.

l 4 n wm be observed that the sous la sns u are so wound and connectedthat if current is applied thereto to produce a downwardly directedmagneto-motive force in one of these coils this same current willproduce an upwardly directed magneto-motive force in the other coil. andvice versa. It will also be observed that the permanent magnets PMI andPM2 both have their north pole N adjacent the middle leg Il and havetheir other or south pole B. against the associated outer leg of thecore structure II- I2. The magnetism produced by the permanent magnetsPMI and PM2 has been conventionally shown in Fig. 1 of the drawings bydotted lines containing arrows. From this it will be seen that magnetismflows upwardly through the middle leg II. separates at the upper end oithis leg and substantially equally divides so that substantially equalamounts now downwardly through the legs I0 and I2 back to the southpoles S oi these permanent magnets. The core structure Ill-I2 ispreferably constructed of low reluctance soft iron such as annealedsilicon steel so that this core structure serves as a very efficientshunt for shunting the magnetism emitted by the permanent magnets PMIand PM2 away from the armature A. so that insu!- ficient magnetism willpass through the amature A to pick it up, and so that this armatureremains in its retracted position.

Operation-Figs. 1, 2 and .1 -Referring now to Fig. 3 of the drawings.this drawing shows the same structure as illustrated in Fig. 1 exceptthat direct current is assumed to be passed through the circuitincluding the two coils Il and I4 in series as conventionally shown bybeing connected to wires having and direct current applied thereto asillustrated. It will be observed that the current ow through the coilsI3 and I4 is in a direction to augment the magnetism in the leg III ofthe relay but so as to decrease the amount of magnetic flux in the legI2 of the relay, the amount of iiux existing in the middle leg remainingsubstantial- Since the direction of current flow is such that theshunting eiiect of the portion from leg II to leg I2 of the back yokestructure III-I2 is less than it was heretofore but the shunting effectfor the left-hand portion of the relay (leg I0 to leg I I) is morepronounced than it was heretofore it will be seen that part of the fluxemitted by the permanent magnet PM2 must find new paths and will passthrough the right-hand portion of the armature A to thereby cause thisarmature to be attracted toward the pole pieces 2li, 2| and 22 to anextent in engagement with the residual pins 21. It will be observed thatthe magnetism passing through the right-hand portion of the armature A(Fig. 3) must pass through the conducting washers or slugs I6 and I'I.This magnetism after it has once been built up will not readily fall tozero by reason of the currents induced in these slugs or washers I6 orI'I of good wnducting material. These currents produce magneto-motiveforces tending to maintain such magnetic flux. For this reason, if thecurrent in the circuit for the coils Il and I4 is suddenly reversed. asmay be a common occurrence when the invention is practiced in therailway signalling field, this flux in the right-hand portion of therelay armature and passing through the slugs i8 and I1 will bemaintained for a longer time than is necessary for flux to be built upin the left-hand portion of the relay during pole changing of itsenergizing circuit. The armaopening of the energizing circuit will alsonot cause momentary dropping of the amature A by reason of the`sustaining effect produced by the slugs or washers I6 and I'I of copperor other low resistance conducting material.

It should be understood that, if desired, one of the permanent magnetsPMI and PM2 of the Fig. 1 structure may be turned end-for-end if thedlrection of turns in one oi coils I3 and I4 is also reversed. In suchmodified arrangement there would then be normally practically nomagnetism passing through the middleleg II, so that the cross-section ofthis middle leg could be somewhat reduced.

Structure-Fig. 4.-In Fig. 4 of the drawings has been illustrated amodified form of the invention and embodying the same operatingprinciples as those embodied in the form shown in Figs. 1, 2 and 3. Theprincipal difference between the structure shown in Fig. 4 and thatshown in Fig. 1 is that two independent magnetic circuits are providedin the Fig. 4 structure whereas in the Fig. l structure the middle legis common to the two electro-magnets including coils I3 and I4respectively. It will be observed that in Fig. 4 two U-shaped cores areprovided with contact legs 40 and 4I and legs 42 and 43 respectively.These U-shaped cores are bridged by permanent magnets PMS and FM4respectively which are shunted by leakage strips LS3 and LS4respectively. It will be observed that the four legs 40, 4i, 42 and 43having pole pieces 60, 6I, 62 and 63 respectively are provided withconducting washers or slugs 44, 45 and 41. are preferably double, thatis, are single washers having two holes therein. The coils 50, 5I, 52and 53 contained on these legs 40, 4I, 42 and 43 respectively are sowound and connected that the magneto-motive forces produced by thesecoils, when current is passed through the circuit including these coilsin series, is such that when such current iiows in one direction theinduced magneto-motive forces for the left-hand structure will be in thesame direction in the closed magnetic circuit as the magneto-motiveforce produced by the permanent magnet PM3 whereas for the right-handstructure it will be in a direction in the closed magnetic circuit tooppose the magneto-motive force of the permanent magnet PM4 and that thereverse will be the case when the direction of this current iiow in suchcircuit is reversed. As shown, the legs 4I and 42 are held in rm spacedrelationship at their lower end by double washer 45 and are held in firmspaced relationship at the upper end by a block 46 of nonmagneticmaterial. in other words, the Fig. 4 structure really comprises twomagnetically isolated relay core and coil structures such as disclosedin the Duffy patent constructed to act on the same tractive typearmature of soft iron and these structures are so connected in theiroperating circuit that one of these relay structures will attract thearmature when current iiows in one direction and the other relaystructure will attract the armature when the current flows in theopposite direction, together with means for rendering both of theserelay structures slow releasing. It is thus seen that the functionalresult of the relay shown in Fig. 4 is substantially the same as that ofthe relay structure illustrated in Fig. 1 of the drawings for whichreason it is deemed unnecessary to speciiically consider the operationof the relay illustrated in Fig. 4 of the drawings.

The washers 45 6 The leakage strips LSI and L82 of Fig. 1 and theleakage strips LSB and LS4 shown in Fig. 4

are not only desirable to prevent destruction of the permanent magnetsas by lightning but they are also desirable to prevent destruction ofthe permanent magnet when excessive currents are applied to the relay,in that such current if oi one polarity opposes one of these permanentmagnets and ii of another polarity opposes the other oi.' thesepermanent magnets. In spite of the advantages afforded by these leakagestrips the retained neutral relay of this invention does not necessarilyincorporate or require them and they may be omitted, if desired.

It should be understood that the neutral retained relay of the presentinvention may be either included in series in a control circuit or maybe connected in multiple thereto. Also, if such neutral retained relayincludes two or more windings these windings may be connected in series,in multiple or in series-multiple.

Having thus shown and described several embodiments of the presentinvention it should be understood that they do not include al1structural forms that may be used in practicing the invention and thatthe particular embodiments illustrated have been selected to facilitatedisclosing the underlying principles of the invention and its mode ofoperation and that various changes, modifications and additions may bemade to the disclosure shown in practicing the invention withoutdeparting from the spirit and scope of the invention so long as thesechanges come within the scope of the following claims,

What we claims as new is:

l. In a relay of the character described, an armature normally assuminga retracted position, electro-magnetic means comprising twoelectro-magnetic structures located adjacent said armature and affordingrespective oppositely poled electro-magnetic circuits acting whenenergized with a particular polarity to attract said armature, permanentmagnets magnetically connected in multiple with said electromagneticstructures and so poledas to render one of said electro-magneticstructures effective to attract said armature only when itselectromagnetic circuit is energized with a particular polarity, and asto render the other of said electro-magnetic structures effective toatrract said armature only when its electro-magnetic circuit isenergized with the opposite polarity, a leakage strip in multiple witheach of said permanent magnets, and short circuited turns on each ofsaid magnetic structures near said armature for at times tending tomaintain said armature in its attracted position.

2. In a retained neutral relay, an electro-magnetic core structurehaving two independent legs and one common central leg magneticallyconnected by a common back portion, a single pivoted armaturecooperating with the open ends of the three legs of said core structure,a permanent magnet located between each independent leg and said commonleg, the two permanent magnets having like poles adjacent said commonleg oi said core structure, whereby each permanent magnet normally hasits flux shunted by the adjacent legs and back portion of the corestructure, an energizing winding on that portion of each of saidindependent legs of said core structure which is included in themagnetic shunt for the associated permanent magnet, a short circuitedcoil on each. leg between the permanent magnet and the armature tothereby give a slow releasing eii'ect when the flux has been passingthrough that leg for actuating said armature, whereby the energizationof said windings with one polarity causes iiux to pass through oneindependent leg and said common leg to effectively actuate the amature,whereas the energization of said windings with the opposite polaritycauses iiux to pass through the other independent leg and said commonleg to eRectively actuate the armature, and whereby a quick reversal inthe polarity of energization of said windings or a momentary removal ofenergy from said windings does not cause said armature to release.

3. In a retained neutral relay, two spaced electro-magnetic corestructures each having two independent legs magnetically connected by aback portion, a single pivoted armature cooperating with both of saidcore structures, a permanent magnet located between the open ended legsof each core structure so as to be shunted thereby, a winding on thatportion oi each core structure which is included in the magnetic shuntof the respective permanent magnet. the windings oi' both said corestructures being connected in series, a short circuited coil on thatportion o! each leg of said core structure which does not shunt theassociated ypermanent magnet to thereby give a slow releasing effectwhen that core structure provides magnetic flux for effectivelyactuating the cooperating armature, whereby the energization of saidwindings with one polarity causes magnetic nux from one core structureto effectively actuate the amature, whereas the energization o! saidwindings with the opposite polarity causes flux from the other corestructure to effectively actuate said armature, and whereby a quickreversal of the polarity on said windings does not result in themomentary release of said armature, and said armature is slow inreleasing upon the complete deenergization of said windings.

4. In a retained neutral type relay, a pivoted armature normally biasedto a particular position, a magnetic core structure cooperating withsaid armature for at times actuating it to its opposite position, saidcore structure comprising two permanent magnets and a U-shaped millmeticshunting portion for each permanent magnet, a winding for each shuntingportion, and a leakage member adjacent each permanent magnet andpositioned parallel thereto. a short circuit means associated with saidmagnetic core structure and located thereon adjacent that portion o! thecore structure which brings it into cooperative relation with saidarmature. where# by energization of said windings with one polaritycauses magnetic ilux from one permanent magnet to actuate said armaturewhereas energization of said windings with the opposite polarity causesmagnetic flux from the other permanent magnet to actuate said armature,and whereby the release of said armature is delayed upon thedeenergization of said windings.

JOSEPH E. WILLING. GEORGE J. JOHANEK.

' REFERENCES CITED The following references are of record in the

